Oil refining process



y 11, v. VOORHEES 2,079,886

OIL REFINING PROCESS Filed Dec. 29, 1934 2 Sheets-Sheet 2 OL'L EXTRACT/ON TOWER D54SPH/4LT/NG TANK 5 MPROPAN/ER lus JoLvem;

INVENTOR ATTORNEY Patented May 11, 1937 I l UNITED STATES PATENT OFFICE OIL REFINING PROCESS Vanderveer Voorhees, Hammond, Ind., assignor to Standard Oil Company, Chicago, 11]., a cor- ,poration of Indiana Application December 29, 1934, Serial No. 759,723

2 Claims. (Cl. 196-13) This invention relates to an oil refining process propane can be employed to throw down resins and it pertains more particularly to the sharp which are not usually called asphalt. The fractionation of high quality lubricating oils from word asphalt, as used in this specification and low quality materials and resins with which the in the appended claims, is also intended to in- 5 high quality oils are normally associated. clude resins.

Object of y entio is to Prov d a Referring to Figure 1, a deasphalting tower unique combination of propane treating and solwhich may be a vertical cylindrical pressure t refining P es w er the D ODem -i vessel which is properly insulated and designed soluble material from the former is treated wit to withstand pressures of about 200 to 1,000

10 extract material from the latter so that desirable pounds per square inch is filled with propane at 10 h m ar w i h par fin i r r about 110 F. from line H. Lubricating oil stock covered from asp lts a d r s ns a d a ar is then introduced through line I: at about 150 yield of high quality and interme iate qu ity to 160 F. into the upper part of the tower. The lllbfleeting Oils are Ob ed- A further object asphaltic material is insoluble in the propane and is to decrease the amount of solvent required to being of greater specific gravity it falls to the 15 ta n a v n i d nd qual ty of paraflinic o bottom of the tower and is withdrawn throu from a lubricating oil residuum or distillate. A line l3 to solvent-asphalt tower l4, preferably further object is to provide an improved method in admixture with propane from line IS. The of rectification in the extract end of a solvent propane-Oil solution is withdrawn from the upper 2 eXtraetlOn System. Other objects will become part of the tower through line [6 and introduced app as t following detailed description at the base of solvent tower I! as such or it may of y invention proeeedsbe passed through depropanizer l8 before being Practicing y invention. 1 fi treat the introduced at the base of the solvent tower. The

0 With p p e under conditions which Will fiow of lubricating oil stock and propane into au e the sepeletlon of e propelle-inseluble fracthe deasphalting tower should be so regulated tion. I extract the propane-soluble fraction with t t there is a propane-oil ti of ab ut 4:1 a selective solvent either in the presence or abto 3:1, preferably ;1 h temperature i the sence of propane and I then contact, preferably deasphalting tower is preferably higher at the in a countercurrent manner, the propane-insoluupper end t t th l w nds that the ble fraction from the first step with the extract material discharged through li 13 may be at 30 and solvent from the second step, either separatabout 00 to 1 and the propane ofl 1 ing the rafiinate from this last-named treatment t t th top of th tower may b at ab ut 140 a a ow q y Oil returning it to the Solvent to 160 F. The particular propane ratios and extraction system for increasing the yield of temperatures for obtaining t i d hase h q ty oil. separation can readily be determined by simple 35 The invention will be more clearly understood preliminary tests,

y reference to the p ying drawings In solvent tower I! the propane-soluble oil is w c form a P Of the Specification d in countercurrently extracted with a selective solwhich, vent introduced by line l9, preferably of the type 40 i e 1 represents i diagrammatic eleveexemplified by dichlorethyl ether, phenol, cresol, 40

tion how my invention may be used with countercresylic acid, wood tar acid, nitrobenzene, furcurrent towers; and fural, chloraniline, aniline, sulfur dioxide and Figure 2 represents in diagrammatic elevation benzol, etc. or mixtures of these solvents with how my invention may be employed in continueach other or with other solvents. The charous multiple batch countercurrent extraction acteristic of the solvent is that it is partially systems. miscible with the oil. The solvent-oil ratio and The invention will be described in connection temperature will naturally depend upon the nawith the prepartion of high quality lubricating ture of the solvent used and the desired results, oils from a Mid-Continent residuum, but it should but ordinarily I prefer to employ about one to be understood that the invention is equally apthree volumes of solvent per volume of oil and plicable to any lubricating oil stock which con- I prefer to operate .at about room temperature. tains paraflinic and naphthenic components and High quality oil is withdrawn through line 20 material which is insoluble in propane. The inand any remaining propane and solvent is revention may even be employed on heavy distillate moved therefrom by distillation or chemical stocks and on 1 Pennsylvania oils wherein the means and the oil may be given a finishing treatment such as a contacting to color with clay. These features per se form no part of my present invention and they will therefore not'be described in detail.

The extract from solvent tower I1 is introduced through line 2| into the top of solvent-asphalt,

duction of asphalt into the base of this solventl5 asphalt tower causes the separation of a paraffinic oil phase, which paraffim'c oil moves upwardly in the tower countercurrent to the fiow of solvent and is removed from the top of the tower through line 22. It may be withdrawn through line 23 as an, intermediate or low quality lubricating oil, or it may be passed by line 24 to the depropanizer or by line 25 directly to the solvent tower for increasing the yield of high quality lubricating oil obtainable from the stock 25 undergoing'treatment. Any oil which is withdrawn through line 23 will, of course, have to be freed from propane and solvent and will usually require a finishing treatment with acid or fullers earth in accordance with well known refinery methods.

The material leaving the base of solventasphalt tower l4' through line 26 is essentially asphalt and/or resin and solvent, although it may also contain a small amount of propane. By the process hereinabove described I have recovered from the material rejected by the propaneasphalt tower II) a large amount of high molecular weight parafiinic oil which would otherwise be lost with the asphalt. Also, I have utilized the asphalt to supplement the solvent in this final treatment ofthe extract material from tower l1 and I have combined the asphaltic or naphthenic constituents extracted by the selective solvent with the high molecular weight asphalt rejected by the propane. If there is no recovery of the intermediate quality lubricating oil the solvent tower and the solvent-asphalt tower may be built as a single unit, the material from the base of tower It! being introduced at the base of this unit to serve as a rectification medium to effect the separation and recovery of parafiinic oils.

Referring to Figure 2, I have shown the introduction of propane through line H and oil stock through line l2 into mixer 21 which discharges into deasphalting' tank 28. The temperature of this tank will suitably be between 100 and 180 F., 11101301 less, and may be controlled by regulating the temperature of the incoming stocks or by suitable heating means. The propane-soluble material passes through line 29 to mixer 30 which discharges into separating chamber 3|. In mixer 30, the propane solution is intimately admixed with solvent and extract material which is forced from separator 32 through line 33 by means of pump 34. It may also be nate or high quality oil is withdrawn from the top of settler 32 through pipe 43.

Asphalt from deasphalter 28 may be withdrawn through line l3 to mixer 44 wherein it is mixed with propane from line l5 and solvent and extract material from settler 35 via line 45 and pump 46. This mixture is introduced into settler 41 which is preferably maintained at about to F. Rafiinate from settler 41 is forced by pump 48 through line 49 to mixer 50 wherein it is admixed with extract material from settler 3| via pump 5| and line 52. Instead of returning the rafilnate from settler 35 to mixer 30, I may withdraw it through line 53 as an intermediate or low quality lubricating oil.

Asphalt and the bulk of the solvent are withdrawn through line 54 to suitable propane and solvent recovery means.

From the above description it will be seen that the lubricating oil stock is deasphalted before it comes in contact with the selective solvent and the asphaltic material does not meet the selective solvent until it has reached the very end of its travel through the system. Not only is asphalt eliminated in the raffinate stages of the solvent extraction, but propane may also be eliminated so that in the final rafiinate extraction stages a small amount of solvent will give an excellent yield of a very high quality lubricating oil. The extract from settler 35 may contain a considerable amount of low quality parafiinic lubricating oil and the asphaltic material from line I 3 may contain a large amount of high viscosity paraifinic material which has been rejected by the propane.

When these two materials are intimately admixed with propane and allowed to separate in settler 41, the asphaltic material tends to throw out the intermediate or low quality parafllnic oil and the solvent tends to throw out the high viscosity paraflinic oil which is associated with the asphalt. Thisparaffinic material is further refined in settler 35 by admixture with solvent extract material from settler 3| and I may withdraw the raffinate from settler 35 as an intermediate or low quality lubricating oil or I may return it through line 36 to mixer 30 for combination with the propane-soluble fraction.

It will, of course, be understood that the handling of propane and other hydrocarbon gases such as ethane and butane, suitable for my process, requires the use of superatmospheric pressures. In the case of propane these will usually vary between 100 and 600 pounds per square inch, depending on the temperature. Higher pressures will prevail in the case of ethane. With the latter, however, lower temperatures are required. Apparatus must be built to withstand the high pressure with an adequate factor of safety.

While I have described in detail preferred embodiments of my invention, it should be understood that I do not limit myself to any of the details hereinabove set forth except as defined by the following claims.

I claim:

1. The method of refining a mineral oil containing parafiinic components, naphthenic components and asphalt which comprises treating said oil with a liquefied normally gaseous hydrocarbon selected from the group consisting of ethane, propane and butane under conditions adapted to cause separation of asphalt, extracting the liquefied-hydrocarbon-soluble fraction with a selective solvent, and countercurrently treating the asphalt from the first step with extract material from the second step in the presence of a liquefied normally gaseous hydrocarbon selected components, separating parafllnic components from the group consisting of ethane, propane and butane to recover parafiinic components which would otherwise be discarded with asphalt and extract.

2. The method of refining a lubricating oil stock containing parafiinic components, naphthenic components and asphalt which comprises separating asphalt from parafllnic and naphthenic from naphthenic components by means of a selective solvent to give a raflinate phase and an extract phase, and countercurrently treating said asphalt with said extract phase in the presence of liquid propane to recover intermediate quality paraffinic materials contained in said asphalt and in said extract phase.

VANDERVEER VOORHEES. 

